How do you calculate BOD in water samples?
2.1 Take 50 ml of water sample to be tested in a conical flask. 2.2 Add 2.5 ml of acetic acid diluted to 50% with water. 2.3 Add 2.5 ml of 10% w/v solution of potassium iodide. 2.4 Add 1 ml of starch indicator and titrate with 0.025N sodium sulfite solution.
Why is BOD done for 5 days?
The standard oxidation (or incubation) test period for BOD is 5 days at 20 degrees Celsius (°C) (BOD5). The BOD5 value has been used and reported for many applications, most commonly to indicate the effects of sewage and other organic wastes on dissolved oxygen in surface waters (see TECHNICAL NOTE).
In which water BOD is maximum?
Typical values. Most pristine rivers will have a 5-day carbonaceous BOD below 1 mg/L. Moderately polluted rivers may have a BOD value in the range of 2 to 8 mg/L. Rivers may be considered severely polluted when BOD values exceed 8 mg/L.
What is BOD of drinking water?
BOD is the biochemical oxygen demand of the water and it is related to the concentration of the bacterial facilitated decomposable organic material in the water. For freshwater the concentration should be less than 0.0004 mg/L.
What is the relationship between BOD and DO?
(a) Are directly proportional. Hint: DO are dissolved oxygen and BOD are biochemical oxygen are certain parameters by which one can find out the degree of water pollution or the concentration of readily biodegradable organic matter in the water bodies. …
How is BOD measured for 5 days?
Simply so, how is BOD measured and calculated? Biological Oxygen Demand (BOD): Therefore it is used to measure the amount of certain type of organic water pollution BOD is calculated by keeping a sample of water containing a known amount of oxygen for five days at 20 °C. The oxygen content is measured again and BOD is calculated.
Which is the correct formula to calculate BOD?
BOD is calculated by using the formula BOD = (D1 – D2)/P. Where, D1 = initial dissolved oxygen concentration. D2 = fifth day dissolved oxygen concentration. P = volumetric fraction of wastewater. BOD values range from 1 mg/L for natural waters to about 300mg/L for untreated domestic sewage waters. If the BOD is 300mg/L and above, sewage is said …
How is the biochemical oxygen demand ( BOD ) calculated?
Biochemical oxygen demand (BOD) is the amount of dissolved oxygen needed by aerobic biological organisms.Dilution method is a standard method and it is recognized by EPA. BOD 5 is calculated by: Unseeded BOD 5 = (D 0 – D 5) P. Where, D 0 is the dissolved oxygen (DO) of the diluted solution after preparation (mg/l) …
How to calculate BOD using the dilution method?
BOD Using Dilution Method Biochemical oxygen demand (BOD) is the amount of dissolved oxygen needed by aerobic biological organisms.Dilution method is a standard method and it is recognized by EPA. BOD 5 is calculated by: Unseeded BOD 5 = (D 0 – D 5) P